Exodus 15:25-27 Then Moses cried out to the LORD, and the LORD showed him a piece of wood. He threw it into the water, and the water became fit to drink.
There the LORD issued a ruling and instruction for them and put them to the test. 26 He said, “If you listen carefully to the LORD your God and do what is right in his eyes, if you pay attention to his commands and keep all his decrees, I will not bring on you any of the diseases I brought on the Egyptians, for I am the LORD, who heals you.”
27 Then they came to Elim, where there were twelve springs and seventy palm trees, and they camped there near the water.

Exodus 12:1, 2 The LORD said to Moses and Aaron in Egypt, “This month is to be for you the first month, the first month of your year.

Exodus 7:13 Yet Pharaoh’s heart became hard and he would not listen to them, just as the LORD had said.

Exodus 4:1-5 Moses answered, “What if they do not believe me or listen to me and say, ‘The LORD did not appear to you’?”
2 Then the LORD said to him, “What is that in your hand?”
“A staff,” he replied.
3 The LORD said, “Throw it on the ground.”
Moses threw it on the ground and it became a snake, and he ran from it. 4 Then the LORD said to him, “Reach out your hand and take it by the tail.” So Moses reached out and took hold of the snake and it turned back into a staff in his hand. 5 “This,” said the LORD, “is so that they may believe that the LORD, the God of their fathers—the God of Abraham, the God of Isaac and the God of Jacob—has appeared to you.”

Exodus 3:11, 12 But Moses said to God, “Who am I that I should go to Pharaoh and bring the Israelites out of Egypt?”
12 And God said, “I will be with you. And this will be the sign to you that it is I who have sent you: When you have brought the people out of Egypt, you will worship God on this mountain.